Apparatus and method for controlling laundering cycle by sensing wash aid concentration

ABSTRACT

An automatic washing machine can be operated in accordance with a selected wash cycle by determining a concentration of a wash aid prior to a dispensing of the wash aid into at least one of a tub and a drum, and selecting an operating parameter of the automatic washing machine in response to the determined concentration.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application represents a divisional application of U.S.patent application Ser. No. 12/165,984 entitled “Apparatus and Methodfor Controlling Laundering Cycle by Sensing Wash Aid Concentration”filed Jul. 1, 2008, pending.

BACKGROUND OF THE INVENTION

Conventional automatic cleaning appliances, such as washing machines,dishwashers, and the like, involve the mixing of a wash aid with waterto create a wash liquid to facilitate the cleaning process. These washaids may include detergents, water softeners, fabric softeners,whitening agents, brightening agents, in-wash stain removers, color safebleaches, peroxygen bleaches and the like. One dispensing method is forthe appropriate quantity of wash aid to be added to the cleaningappliance by an operator prior to the initiation of the launderingcycle. The operator places the wash aid in a dispenser, and the wash aidis introduced into the water at a preselected step in the cleaningcycle. The effectiveness of the wash aid is dependent, at least in part,on the quantity of wash aid dispensed. Thus, accurate measuring anddispensing of the wash aid is very desirable.

Certain wash aids, particularly laundry detergents, are increasinglysupplied to the public in higher concentrations, such as twice or threetimes the concentration of a traditional laundry detergent. Thus, forexample, if a traditional laundry detergent has a base concentrationidentified as “1×,” a detergent having twice the concentration or triplethe concentration can be identified as “2×” or “3×”, respectively.Because these detergents are more highly concentrated, a smallerquantity of higher-concentration detergent is required to provide thesame cleaning effectiveness as a 1× detergent.

The more highly concentrated wash aids have created a dispensingproblem. Current dispensing systems are designed for wash aids of aknown and standard concentration, such as the 1× detergentconcentration. If a wash aid of a greater concentration is used, thedispensing system is dependent on the user to place the appropriateamount of wash aid in the dispenser. Unfortunately, reliance on the userprovides a source of dispensing errors, the most likely of which is thefilling of the dispensing system with too much of the higherconcentration wash aid.

Conventional cleaning appliances, such as washing machines anddishwashers, require a specific amount of detergent in order to optimizecleaning and minimize the generation of excess suds, which can bedetrimental to the cleaning process and certain components, particularlypumps. High concentrations of detergent can also be damaging to certainfabrics. The quantity of detergent required will be dependent on theconcentration of the detergent. Thus, for example, if too large aquantity of a high-concentration detergent is dispensed, excessivesudsing can occur, or fabrics can be damaged. Conversely, if too low aquantity of a low-concentration detergent is used, soil removal from thelaundered items can be less effective.

SUMMARY OF THE INVENTION

An automatic washing machine can be operated in accordance with aselected wash cycle by determining a concentration of a wash aid priorto a dispensing of the wash aid into at least one of a tub and a drum,and selecting an operating parameter of the automatic washing machine inresponse to the determined concentration.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective, partly schematic, view of a first embodiment ofthe invention as an automatic clothes washing machine having at leastone concentration sensor, in the form of a refractive index sensorassembly, for determining the concentration of a wash aid.

FIG. 2 is a schematic view of the automatic clothes washing machineillustrated in FIG. 1.

FIG. 3 is a table of the relationship between surfactant concentrationand refractive index according to one embodiment of the invention.

FIG. 4 is a perspective view of a first example of a wash aid dispenserdrawer according to one embodiment of the invention, including at leastone refractive index sensor assembly for sensing the concentration of awash aid contained therein.

FIG. 5 is a perspective view of a second example of a wash aid dispenserdrawer according to one embodiment of the invention, including at leastone refractive index sensor assembly for sensing the concentration of awash aid contained in a bulk dispenser cartridge.

FIG. 6 is a perspective, partly schematic, view of another embodiment ofthe invention as an automatic clothes washing machine having a washliquid concentration sensor, in the form of a refractive index sensorassembly, for determining the concentration of a wash aid in a washliquid in a sump.

FIG. 7 is a schematic view of the automatic clothes washing machineillustrated in FIG. 6.

FIG. 8 is a perspective view of a wash aid dispenser drawer including analternate refractive index sensor assembly according to one embodimentof the invention for sensing the concentration of a wash aid containedtherein.

FIG. 9 is an enlarged, partially cutaway view of the wash aid dispenserdrawer illustrated in FIG. 8 showing the refractive index sensorassembly.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

The invention disclosed herein may be suitable for use in bothhorizontal axis and vertical axis automatic clothes washing machines,automatic dishwashing machines, and other automatic cleaning machinesthat utilize a selected quantity of a wash aid during a cleaningoperation. The invention will be illustrated and described, however, inthe context of a horizontal axis washing machine. Known horizontal axiswashing machines can be characterized by two common types of washingaction and water usage. The first type is known as a “tumble wash;” thesecond type is known as a “recirculating wash.”

In the tumble wash, wash liquid may be added to the tub so that thebottom of the drum and items residing in the bottom of the drum, aresubmerged or partially submerged. As the drum rotates, items are liftedup and dropped into the wash liquid in the bottom of the drum to createa tumbling action of the clothes to impart mechanical energy to theitems to facilitate their cleaning.

In the recirculating wash, the level of wash liquid need not extend intothe drum. Rather, the drum and items to be laundered are rotated whilewash liquid is recirculated from the sump and sprayed on the items,typically from the top of the drum. The force of the liquid sprayedthrough the items facilitates their cleaning. An advantage of therecirculating wash is that less water can be used. The spraying of washliquid on the items may be done while the drum is rotated so thatcentrifugal force helps draw the sprayed wash liquid through the items.The rate of rotation may be high enough that the items remain in contactwith the interior of the drum and do not tumble. This speed is somewhatrelated to the speed at which the centrifugal force acting on the itemsis greater than the force of gravity.

As used in this application, the term “spin” will describe rotationalspeeds sufficient to plaster the items against the drum. The term“tumble” will refer to rotation speeds wherein the items are free totumble while the drum is rotated. The term “rotate” will refer torotation at any speed, and includes both spinning and tumbling.

In the description that follows, a specific functionality relatingexclusively to either the tumble wash or the recirculating wash may beidentified. Otherwise, the functionality will be considered equallyapplicable to both a tumble wash and a recirculating wash.

Referring now to the drawings, and in particular to FIG. 1, a firstembodiment of the invention is illustrated as a horizontal axisautomatic clothes washing machine 10. The clothes washing machine 10 mayinclude a cabinet 12 enclosing components typically found in aconventional washing machine, such as motors, pumps, fluid lines,controls, sensors, transducers, and the like. Such components will notbe described further herein except as necessary for a completeunderstanding of the invention.

A door 14 may be provided for access to the interior a tub 16 and drum17 (FIG. 2) suspended in the interior of the cabinet 12. The interior ofthe drum 17 defines a wash chamber in which the laundry items are placedfor cleaning. The tub 16 may be associated with a sump 18 for carrying aliquid used during a laundering cycle. The cabinet 12 may also enclose adispenser drawer 20 for dispensing liquid laundering aids during alaundering cycle, such as laundry detergent, fabric softener, bleach,in-wash stain removers, color-safe bleaches, peroxygen bleaches, and thelike. The cabinet 12 may include a user interface 22 having operationalcontrols such as dials, lights, switches, and displays enabling a userto input commands to a controller 24 and receive information about aspecific laundering cycle. The user interface 22 may be electricallycoupled with the controller 24 through user interface leads 76. Thecontroller 24 may control a variety of operations, such as controlling aselected laundering cycle, controlling a selected modification to aselected laundering cycle, controlling pumps, motors, and sensors,terminating a laundering cycle in response to an error condition, orcausing an audio or visual signal to be broadcast.

In the embodiment illustrated in FIGS. 1 and 2, the cabinet 12 may alsoenclose a pump 30 fluidly coupled with a water supply 28, and a pair ofvalves 26, 27. The single pump 30 is illustrated for introducing freshwater from the water supply 28 into the sump 18, the tub 16, or thedispenser drawer 20. The pump 30 is illustrated as fluidly coupleddirectly with the sump 18 through a sump line 34. The pump 30 is alsoillustrated as fluidly coupled to the valve 27 through a recirculatingline 36. The valve 27 may be fluidly coupled through a recirculatingline 42 with the tub 16 for recirculating wash liquid from the sump 18to the tub 16. The valve 27 may also be fluidly coupled to the dispenserdrawer 20 for delivering fresh water from the pump 30 to the dispenserdrawer 20.

The dispenser drawer 20 may also be fluidly coupled through a dispensingline 38 with a valve 26, which may in turn be fluidly coupled with thetub 16 through a dispensing line 40. Fresh water may be delivered fromthe pump 30 through the valve 27 and the flush line 44 into thedispensing drawer 20 for flushing a laundering aid from the dispensingdrawer 20 through the dispensing line 38, the valve 26, and thedispensing line 40 into the tub 16. The valve 26 may be electricallycoupled with the controller 24 through a valve control lead 56. Thevalve 27 may be electrically coupled with the controller 24 through avalve control lead 46. The controller 24 may control the operation ofthe valves 26, 27 in response to instructions received from the userinterface 20 as a result of selections made by the user, such aslaundering cycle, water temperature, spin speed, extra rinse, and thelike.

The washing machine 10 illustrated in FIGS. 1 and 2 is only one exampleof a washing machine configuration. It will be recognized that severalpumps may be utilized for selected functions, a fewer or greater numberof valves may be utilized depending upon the selected fluid lineconfiguration and degree of control desired, and control leads may beincorporated into the device based upon the components for which controlby the controller 24 may be desired.

Laundering aid sensors may be provided. For example, sensor assembliesmay be used to determine the concentration of laundry detergent, eitherundiluted or as mixed with water to form a wash liquid. The launderingaid sensor assembly may include a dispenser sensor 80 associated withthe dispenser drawer 20 for sensing the undiluted laundry detergent, andmay be electrically coupled with the controller 24 through a dispensersensor lead 48. The sensor may be a refractive index sensor, such as aModel DGWS1 liquid refractive index sensor, available from Thorlabs ofNewton, New Jersey. While a refractive index sensor is illustrated anddescribed, other sensors may also be used. For example, the sensor maybe a resistivity sensor having a pair of electrodes in contact with thelaundering aid, a pH sensor, an oxidation/reduction sensor, a chemicalsensor, and the like, capable of generating a signal proportional to theconcentration of the laundering aid.

As illustrated in FIG. 2, the refractive index sensor assembly maycomprise a transmitter 52 and the sensor 80, whereby a beam of light maybe projected through the undiluted laundering aid from the transmitter52 onto the sensor 80, which generates a signal indicative of theconcentration of the undiluted laundering aid. This signal may bedelivered to the controller 24 through a dispenser sensor output lead72.

FIG. 3 is a table illustrating the refractive index for differentconcentrations of detergent from different manufactures. It can be seenfrom the tabular data that there is a general correlation between thepercentage of surfactant and the refractive index for a detergent. Therefractive index tends to increase as the percentage of surfactantincreases. This general correlation is strong enough that the refractiveindex may be used to determine between classes of concentrations, suchas 1× and 3× detergents.

While the general correlation between refractive index and percentsurfactant is sufficient to determine between classes, there isvariation in the refractive index within a given concentration range,which is not solely attributable to the variations of the percentsurfactant. These variations are thought to be attributable to otheringredients in the detergent. These variations are also partlyattributable to not all classes of detergents have the same identicalpercentage of surfactant.

It has been noted that each detergent has a unique refractive index. Inthis way, the refractive index may be used as an identifier for aspecific detergent. A database or table of information may be createdshowing the refractive index for each type of detergent. This databasemay be used by the controller to look up the specific detergent based onthe sensed refractive index and determine the correspondingconcentration.

Thus, the refractive index information may be used in at least two ways,separately or in combination, to determine the concentration of thedetergent and to use that information to control the dispensing of thedetergent. The first way is to use the refractive index to make ageneral determination regarding the class of detergent (1×, 2×, 3×,etc.). The general class determination is useful in making generaldistinctions, but it does not give specific information about aparticular detergent's concentration. The second way is to use therefractive index to identify the detergent and look up the correspondingconcentration. The look up method is useful in that the exactconcentration values may be determined. For example, an advertised 1×detergent may actually have a 1.2× concentration or a 0.8×concentration.

One implementation of this method would be to first use the refractiveindex to identify the detergent as this will provide the most accurateresults. If a match is not found, then the refractive index may be usedto make a general class determination.

FIG. 4 illustrates an example of a dispenser drawer 20 that may be usedwith the washing machine 10. The dispensing drawer 20 may have aplurality of refractive index sensor assemblies for determining theconcentrations of several laundering aids. The dispenser drawer 20 asillustrated has a front wall 90, a rear wall 92, a pair of sidewalls 94,96, and a bottom wall 98. Extending laterally between the sidewalls 94,96 may be a rear transverse wall 100 and a medial transverse wall 102.Extending longitudinally between the front wall 90 and the medialtransverse wall 102 may be a longitudinal wall 104. The walls extendgenerally orthogonally to the bottom wall 98 and define laundering aidcompartments 106, 108, 110. The laundering aid compartments may holdliquid laundering aids, such as laundry detergent, fabric softener,bleach, in-wash stain removers, color safe bleaches, peroxygen bleaches,and the like.

A first transmitter 112 and a first sensor 114 may be associated withthe first laundering aid compartment 106. The first transmitter 112 maybe mounted to the bottom wall 98, with the first sensor 114 mounted inthe medial transverse wall 102 to receive a beam of light transmitted bythe first transmitter 112 through the laundering aid in the firstlaundering aid compartment 106. The first transmitter 112 and firstsensor 114 may be electrically coupled with the controller 24 throughsuitable electrical leads, such as a wiring harness, for control andprocessing of the input and output from the transmitter 112 and sensor114. The first transmitter 112 and first sensor 114 may be configured sothat the transmitter 112 may transmit a beam of light through thelaundering aid regardless of the quantity of laundering aid in the firstcompartment 106. As illustrated, this configuration locates thetransmitter on the bottom wall of the dispenser with it being aimedupwardly toward a receiver 122 on the side wall. Alternatively, thefirst transmitter 112 and first sensor 114 may be mounted in the sidewall 94 and longitudinal wall 104, respectively, sufficiently near thebottom wall 98 to ensure that the light beam passes through thelaundering aid. The transmitter 112 and the sensor 114 may be configuredto determine when the first laundering aid compartment 106 may be empty.This may be based upon the different refractive index outputs from thesensor 114 when liquid is present in the compartment 106 and when it isnot. In an alternate embodiment, the transmitter and the sensor aremounted on or adjacent to the same wall of the dispenser. This willenable the transmitter and sensor to be incorporated into a singleapparatus. The light beam from the transmitter will be modulated so thatit does not pass through the liquid, but is reflected internally to thesensor at the sensor-laundry aid interface. This alternate embodiment isdescribed in greater detail hereinafter.

The second laundering aid compartment 108 may have a similarlyconfigured transmitter 116 and sensor 118 configured for transmission ofa beam of light through the laundering aid regardless of the quantity ofliquid laundering aid 128 in the second compartment 108. The secondcompartment 108 may also be provided with a liquid height transducer 124associated with the side wall 96 for monitoring the height of the liquidlaundering aid 128 in the compartment 108. The liquid height transducer124 may be utilized to alert the operator if the second compartment 108is empty. In other embodiments of the invention, the liquid heighttransducer 124 may also be utilized to determine the volume of liquidlaundering aid 128 in the compartment 108. Alternatively, the refractiveindex output from the sensor 118 may be utilized to determine when thecompartment 108 is empty, as described above.

Each of the laundering aid compartments 106, 108, and 110 may include adispenser siphon or suction pipe 84, 86, 88, respectively, whose top maybe below the top of the corresponding compartment. To dispense thelaundering aid placed in a compartment, water may be added to theselected compartment until the liquid is above the pipe, at which pointthe liquid may be drawn by gravity into the pipe, which initiates asiphon process for removing the liquid from the compartment. Water maybe added until it is reasonably certain that substantially all of thelaundering aid is dispensed from the compartment. This is referred to as“flushing” the laundering aid compartment. Other dispensing methodsknown to those skilled in the art may also be used to remove thelaundering aid form the various laundering compartments 106, 108, 110.While not shown in FIG. 4, the suction pipes may lead to a housing thatunderlies the drawer 20. The housing may be fluidly connected to thedispensing line 38 such that the liquid exiting the suction pipe duringflushing may be directed to the tub 16.

The third laundering aid compartment 110 may have a similarly configuredtransmitter 120 and sensor 122 configured for transmission of a beam oflight through the laundering aid regardless of the quantity of liquidlaundering aid in the third compartment 110. The third compartment 110may be provided with a liquid height transducer 126 associated with theside wall 96 for monitoring the height of the liquid laundering aid inthe compartment 110. An empty compartment 110 may also be determinedfrom the refractive index output from the sensor 122, as describedabove.

Alternatively, the volume of laundering aid in a compartment may bedetermined from the incorporation of a weight or mass sensor into thecompartment containing the laundering aid. Similarly, the control of theoperation of the washing machine 10 may be correlated to the weight andconcentration of the laundering aid rather than its volume andconcentration.

The foregoing descriptions are of exemplary sensor locations. Otherlocations may be utilized for a transmitter and sensor, for example,incorporated into the valve structure 26, incorporated into thedispensing line 38, or incorporated into an auxiliary receptacle (notshown) which may be part of the dispenser drawer 20 or associated with abulk dispenser coupling apparatus.

A first example of control of the laundering cycle will now be describedwith respect to the addition of a liquid laundry detergent to the secondlaundering aid compartment 108. Operating parameters that may becontrolled may include sensing a refractive index of the laundering aid,controlling a quantity of water introduced into the automatic washingmachine based on a sensed concentration of a laundering aid, controllinga flushing of the laundering aid from the laundering aid dispenser,controlling the flushing based on a sensed concentration of a launderingaid in one of the tub and the drum, maintaining the generation of sudswithin one of the tub and the drum below a preselected limit, adding atleast one rinse step to the wash cycle, dispensing a preselectedquantity of a laundering aid based on the determined concentration,halting the wash cycle, generating an audio signal, generating a visualsignal, generating an error code, dispensing a quantity of a sudsreducer based on the determined concentration, and the like.

In this example, a user will select a laundering cycle and will pour aselected volume of a laundry detergent into the laundering aidcompartment 108. The user interface 22 may include a selector so thatthe user may select a concentration of laundry detergent being used,such as a 2× detergent. The controller 24 may have stored in memory atabulation of data relating to a predetermined volume of detergent of aselected concentration for each selectable laundering cycle. Thus, forexample, for a given laundering cycle, the tabulation may indicate thata first volume of a 1× detergent will be appropriate, a second volume ofa 2× detergent roughly equivalent to half the first volume will beappropriate, a third volume of a 4× detergent roughly equivalent to onequarter the first volume will be appropriate, and so on.

After the user introduces the detergent into the dispenser drawer 20,the second transmitter 116 and second sensor 118 may be actuated todetermine the concentration of the detergent. If the user has selected a2× detergent on the user interface 22, the controller 24 may confirmthat the proper concentration detergent, i.e. a 2× detergent, ispresent, and proceed with the laundering cycle. If the user has selecteda 1× detergent on the user interface 22, but has introduced a 4×detergent into the dispenser drawer 20, the controller 24 may provide aresponsive action. For example, the controller 24 may terminate thelaundering cycle, cause an audio or visual warning signal to bebroadcast, or a combination of termination and a warning signal.Alternately, the controller 24 may override the user selection andoperate based on the determined concentration.

If the user mixes two laundering aids having different concentrations,e.g. 1× and 2× detergent, the controller 24 can be adapted to determinethe effective concentration of the mixture, e.g. 1.37×, based upon theoutput from the sensor, and determine the quantity of laundering aid todispense.

If the second laundering aid compartment 108 may be provided with aheight transducer 124, the controller 24 may determine both theconcentration of the detergent and the height (and thus the volume) ofdetergent in the laundering aid compartment 108.

FIG. 5 illustrates another example of a dispenser drawer 190 suitablefor use with the automatic clothes washer 10. The dispenser drawer 190may be configured for receipt of a bulk dispenser cartridge 140, alsoreferred to as a “mini-bulk dispenser.” An example of such a bulkdispenser cartridge is described and illustrated in concurrently-filed,commonly-owned U.S. patent application Ser. No. 12/165,712, filed Jul.1, 2008, entitled “A Household Cleaning Appliance With A DispensingSystem Operable Between A Single Use Dispensing System And A BulkDispensing System,” bearing Applicant's docket number US20080054, whichis incorporated herein by reference in its entirety. The dispensercartridge 140 contains a quantity of a laundering aid, such as a laundrydetergent, sealed therein behind a slidable door 143 (shown open in FIG.5) and sufficient for several laundering cycles, for example, 8-10laundering cycles. The use of the dispenser cartridge 140 eliminates theneed for a user to measure out a selected volume of laundering aid foreach laundering cycle.

The dispenser cartridge 140 may be a generally rectilinear, box-likecontainer sized to be received within a laundering aid compartment 142of the dispenser drawer 190. The cartridge may have a front wall 144, apair of parallel side walls 146, 148, a rear wall 150, a top wall 151with the slidable door 143, and a bottom wall 152 defining a cartridgecavity in which the laundering aid may be contained. The slidable door143 may be formed in the top wall 151, and provides for ready refillingof the cartridge 140. Each side wall 146, 148 may be provided with asensor window 154, 156, respectively, the sensor windows 154, 156 beingaligned for the transmission of a refractive index sensor light beamthrough the laundering aid.

Although the bulk dispenser cartridge has been described as arectangular box-like container, the bulk dispensing cartridge may be anytype of removable container configured to store multiple doses of atreating chemistry. The container may have any shape and size that isreceivable within the dispenser. The removable container may beflexible, rigid, expandable, or collapsible. The container may be madeof any type of material. Some examples of suitable cartridges are,without limitation, a plastic container, a cardboard container, a coatedcardboard container, and a bladder, all of which are capable of beingreceived within the dispenser.

The dispenser drawer 190 may incorporate a transmitter 158 and a sensor160 mounted therein for projection of a light beam from the transmitter158 through the windows 154, 156 and the laundering aid, to be receivedby the sensor 160 for determining the refractive index of the launderingaid. The transmitter 158 may be electrically coupled with the controller24 through a transmitter lead 162. The sensor 160 will be similarlycoupled with the controller 24.

The dispenser drawer 190 may also be configured with a suitable fluidconnector for connecting the dispenser cartridge 140 into a launderingaid dispensing line, such as the dispensing line 38 illustrated in FIGS.1 and 2. The dispenser cartridge 140 may also be fluidly coupled with avalve for controlling the dispensing of laundering aid into thedispensing line, such as the valve 26 illustrated in FIGS. 1 and 2.

After the dispenser cartridge 140 has been properly installed in thedispenser drawer 190, a selected volume of laundering aid may bedispensed from the dispenser cartridge 140 through operation of thevalve 26 under the control of the controller 24. This may beaccomplished by the user selecting a volume of laundering aid on theuser interface 22. Alternatively, this 0 may be accomplished byselecting a laundering cycle on the user interface 22, which may then beprocessed by the controller 24, along with a determination of the sizeof the load, to automatically dispense the appropriate volume oflaundering aid.

The use of the refractive index sensor assembly enables precise controlof the volume of laundering aid dispensed. For example, if a selectedlaundering cycle and wash load size correspond with a predeterminedvolume of laundering aid having a selected concentration to provideoptimal laundering, the refractive index sensor assembly may determinethe concentration of the laundering aid, and the controller 24 maycontrol the valve 26 to dispense the predetermined volume of launderingaid for the selected laundering cycle and wash load size. Alternatively,if the concentration of the laundering aid may be inputted by a userthrough the user interface 22 into the controller 24, the refractiveindex sensor assembly may confirm that the concentration of thelaundering aid in the dispenser cartridge 140 is indeed theconcentration entered by the user. If an adjustment in volume may benecessary to account for a difference in concentration from that inputinto the controller 24, the controller 24 may control the valve 26 todispense the appropriate volume of laundering aid.

The refractive index sensor assembly may be used in a similar manner tocontrol the volume of laundering aid dispensed from a large bulklaundering aid container (not shown). The bulk container may hold aquantity of laundering aid sufficient for a relatively large number oflaundering cycles. The large container may not be utilized with adispenser drawer, but may be fluidly coupled with the washing machine 10through a dispenser fitting incorporated into the washing machine 10, inwhich the large container may be seated. The large container may becoupled with the washing machine 10 through a liquid-tight coupling (notshown), such as a quick-connect coupling assembly. The coupling may befluidly connected to the valve 26, or to a dedicated dispensing valve(not shown) incorporated into the dispenser fitting.

As with the user-dispensed laundering aid described above, otherremedial actions may be taken in response to a discrepancy in the actualconcentration of the laundering aid versus a selected or expectedconcentration. These may include, for example, termination of thelaundering cycle, adjustment of the volume of water utilized in the washliquid, generation of audio or visual signals, dispensing of a sudsreducer, and the like. Audio signals may include a tone, or aprerecorded message, such as “Add 3 milliliters of detergent.” Visualsignals may include a steady or blinking light, or a visual display onthe user interface 22 which indicates the actual concentration of thelaundering aid, or the volume of laundering aid to be added.

If the laundering cycle has proceeded with a wash liquid having a higherconcentration of laundering aid than appropriate, rinse steps mayproceed with additional rinse water, or additional rinse steps may beutilized in order to remove excess laundering aid that may be present inthe laundered items. An extra spin step, or a higher speed spin step,may also be utilized between the wash step and rinse steps to assist inthe removal of excess laundering aid. For example, the spin speed may beincreased to 1000-1400 rpm from a normal spin speed of 700-800 rpm.

A refractive index sensor assembly may be utilized to determine theconcentration of the undiluted laundering aid. This will lead to themost accurate control of the dispensing of the laundering aid and theselection of appropriate operational conditions. Alternatively, arefractive index sensor assembly associated with the sump 18 may beutilized in place of a dispenser refractive index sensor assembly,particularly where a bulk laundering aid dispenser may be utilized,since a bulk laundering aid dispenser may enable adjustments,particularly additions, to the quantity of laundering aid dispensed tobe made after the initiation of the laundering cycle based upon theconcentration determined from the sump refractive index sensor assembly.Alternatively, a sump refractive index sensor assembly may be utilizedin combination with a dispenser refractive index sensor assembly toconfirm that the concentration of laundering aid in the wash liquid maybe appropriate. A sump refractive index sensor assembly may be somewhatless practicable, however, because the wash liquid in the sump willcontain varying quantities of soil from the different laundering cyclesand items being laundered, which will affect the accuracy of theconcentration determination.

Another embodiment is illustrated in FIG. 6, which shows a washingmachine 200 which shares many of the elements of the washing machine 10.Thus, like elements in both embodiments will be identified with likenumbers. The sump 18 in the embodiment of FIG. 6 includes a refractiveindex sensor assembly having a transmitter 54 that may project a beam oflight through the wash liquid in the sump 18 onto a sensor 82, whichgenerates a signal which may be proportional to the concentration oflaundering aid in the wash liquid in the sump 18. As illustrated in FIG.7, the signal may be delivered through a sump sensor output lead 74 tothe controller 24, which may control selected functionalities of thewashing machine 200 based upon the concentration of the laundering aidin the wash liquid in the sump 18. The sump refractive index sensorassembly operates in generally the same manner as thepreviously-described refractive index sensor assembly associated with adispenser drawer. FIGS. 6 and 7 illustrate a washing machine 200 havinga sump refractive index sensor assembly with a dispenser refractiveindex sensor assembly. However, the washing machine 200 can be providedwith the sump refractive index sensor assembly alone.

If the second laundering aid compartment 108 may be provided with aheight transducer 124 (FIG. 4), the controller 24 may determine both theconcentration of the detergent and the height (and thus the volume) ofdetergent in the laundering aid compartment 108. If the volume of a highconcentration detergent may be too great for the selected launderingcycle and may result in excessive sudsing, for example, the controller24 may control the volume of detergent dispensed from the dispenserdrawer 20, instead of flushing all of the detergent from the dispenserdrawer 20. The dispensing process may proceed by flushing a selectedvolume of detergent from the dispenser drawer 20, followed by adetermination of the concentration of the detergent in the wash liquidin the sump 18. The controlled dispensing may also be accomplished byeither dispensing a sufficient volume of water through the secondcompartment 108 to provide a wash liquid with an appropriateconcentration of detergent based, for example, upon a sensedconcentration of the detergent in the dispenser drawer 20, removing aselected volume of detergent from the second compartment 108 prior toadding the water, or dispensing a suds reducer, for example, from thethird laundering aid compartment 110.

Other methodologies for controlling the flushing process by determiningthe concentration of the detergent in the wash liquid in the sump 18 mayinclude multiple discrete flushing steps, with the concentrationdetermined after each discrete flushing step, continuously flushinguntil the flushing may be halted based upon a determined concentration,flushing prior to the wash liquid reaching a desired volume, and addingwater to the wash liquid to reach a selected volume without flushingadditional laundering aid from the dispenser drawer 20, and flushing anyremaining laundering aid from the dispenser drawer 20 after thecompletion of the selected laundering cycle.

If a low concentration detergent has been added instead of a higherconcentration detergent, in a volume that may be too small for theselected laundering cycle, the controller 24 may control the volume ofwater added to the second compartment 108 to provide a wash liquid withan appropriate detergent concentration. If the resulting volume of washliquid may be too small for the selected laundering cycle, thecontroller 24 may add a controlled volume of water in order to optimizethe quantity of wash liquid with the detergent concentration, and mayincrease the duration of the laundering cycle to accommodate the lowerconcentration wash liquid and provide satisfactory laundering of theitems.

Alternatively, if a low concentration detergent has been added, thethermal content, i.e. the temperature, of the wash load can be increasedeither by actuating a heater in the sump, or adding warm/hot water fromthe water supply 28. In one embodiment of the invention, the temperaturecan be increased 5-10° C. (9-18° F.) to ensure optimal performance withthe lower detergent amount. Additionally, a message can be communicatedto the user before this thermal option is implemented.

If the automatic clothes washing machine 10 is a “recirculating wash”machine, or if the washing machine 10 is selectively capable of both a“tumble wash” and a “recirculating wash,” and a “recirculating wash” hasbeen selected, an excessive quantity of laundering aid resulting from,for example, selection of a lower concentration laundering aid thanactually provided may be remedied by the addition of water to the washliquid, as previously described. Depending upon the resulting volume ofwash liquid, the recirculating wash may be utilized as selected, or thelaundering cycle may continue as a “tumble wash” in order to avoid thegeneration of excessive suds or damage to laundered items from the highconcentration laundering aid.

FIG. 8 illustrates an alternate embodiment of a refractive index sensor210 for incorporation into a wash aid dispenser drawer 20. The dispenserdrawer 20 may be provided with a sensor wall 212 in a laundering aidcompartment to define a chamber in which the sensor 210 may be located.The wall 100 separating the chamber from the third laundering aidcompartment 110 may be provided with a sensor opening 214.

Referring to FIG. 9, a suitable refractive index sensor 210 may be aSpreeta™-R sensor manufactured by Sensata Technologies of Attleboro,Mass. The sensor 210 includes a base 216 and a housing 218. The housingmay be fabricated of a clear material, such as a plastic. The housing218 includes a glass sensing interface 228 and a reflector 230. The base216 includes a light source 220 and a photodiode array 222. The lightsource 220 may comprise one or more light emitting diodes (LEDs)configured to focus light at an angle onto the sensing interface 228. Afocusing apparatus 224 may be positioned above the light source 220 andmay comprise an aperture 226 for focusing a light beam 232 onto thesensing interface 228. The refractive index sensor 210 may be mounted inthe wash aid dispenser drawer 20 so that the sensing interface 228 maybe in registry with the sensor opening 214 and can contact the wash aid.

The sensor 210 is based on the optical phenomena of surface plasmonresonance, which occurs when light interacts with a free electronmaterial. In operation, the light from the light source 220 reflectsinternally off the liquid-glass interface between the sensing interface228 and the wash aid. The light then reflects off the minor 230 and ontothe photodiode array 222. Depending on the refractive index of theliquid, light striking the surface above a certain angle will betransmitted through the liquid-glass interface instead of beinginternally reflected. This angle is called the critical angle. Thisphenomenon results in a dark area or shadow-line on the photodiodearray. The location of the shadow-line is indicative of the refractiveindex. As the refractive index changes, the critical angle also changesand is sensed as a new shadow-line location.

The refractive index sensor 210 can also be mounted in a similar mannerin a reservoir downstream of and fluidly coupled with the dispenserdrawer 20. In either case, the refractive index sensor 210 will beelectrically coupled with the controller 24 so that the concentration ofthe wash aid determined by the refractive index sensor 210 may beutilized to control the wash cycle as hereinbefore described.

With this configuration, the sensing apparatus can be contained entirelyon one side of the wash aid or laundering aid compartment. Additionally,only one window into the wash aid is required, and fewer electricalconnections are required.

While the invention has been specifically described in connection withcertain specific embodiments thereof, it is to be understood that thisis by way of illustration and not of limitation. Reasonable variationand modification are possible within the scope of the forgoingdisclosure and drawings without departing from the spirit of theinvention which is defined in the appended claims.

What is claimed is:
 1. A method for operating an automatic washingmachine in accordance with a selected wash cycle, the automatic washingmachine comprising a wash chamber, a wash aid dispenser fluidly coupledto the wash chamber, and a water supply fluidly coupled to the washchamber, the method comprising: dispensing a wash aid from the dispenserto form a wash liquid in the wash chamber; determining a concentrationof the wash aid in the wash liquid in the wash chamber; and halting thedispensing of the wash aid when the determined concentration is suitablefor the selected wash cycle.
 2. The method in accordance with claim 1wherein the dispensing comprises multiple discrete dispensing processesand the concentration is determined after each discrete dispensingprocess.
 3. The method in accordance with claim 1 wherein the dispensingcomprises a continuous dispensing until the flushing is halted.
 4. Themethod in accordance with claim 1 wherein the halting of the occursprior to the wash liquor reaching the desired volume and water is addedto the wash liquor to reach the desired volume without dispensingadditional wash aid.
 5. The method in accordance with claim 4 whereinany remaining wash aid is dispensed from the dispenser after thecompletion of the selected wash cycle.
 6. The method in accordance withclaim 1 wherein the dispensing comprises flushing the wash aid from thedispenser.